Some pharmaceutically active components which cause gelation under a certain condition have been known (Patent Literatures 1 to 7 and Non-Patent Literatures 1 and 2). In general, when a solid dosage form is orally administrated, the solid dosage form readily disintegrates in the gastrointestinal tract to dissolve a pharmaceutically active component, whereby the pharmaceutically active component is absorbed into the body. However, when a solid dosage form containing a pharmaceutically active component which, causes gelation is administrated, there arises such a problem that gelation of the active pharmaceutical ingredient delays the disintegration of the solid dosage form, and delays the dissolution of the pharmaceutically active ingredient.
As conventional techniques of improving delayed disintegration due to gelation, a method of adding cyclodextrin to suppress gel formation or secure the water permeability of a gel layer (Non-Patent Literatures 1 and 2), a method of adding a disintegrant (Non-Patent Literature 1), a method of adding a silicic acid or a silicate (Patent Literatures 1 to 3), a method of making a drug finer and causing the drug to be adsorbed to a carrier (Patent Literature 4), a method in which a film coating is rapidly broken to disintegrate a drug-containing core before gelation (Patent Literature 5), a method using an acidic or basic additive (Patent Literature 6), a method of achieving a form of molecular dispersion such as dispersion of a drug in a polymer (Patent Literature 7), and a method of adding a sugar alcohol (Patent Literatures 8 to 10) have been known.
Further, as a dosage form containing a quinolone carboxylic acid antimicrobial agent in which a main drug is stabilized, an oral composition containing an acidic additive (Patent Literature 11) and a dosage form for injection containing an acidic additive (Patent Literatures 12 and 13) have been known.